Using ROC curve analyses, biomarkers that differentiated AKI from healthy control subjects included GSTA1, Osteoactivin, and Renin, whereas GSTA1, Renin, RBP4, EGF, MCP-1, Uromodulin, α1-microglobulin, TFF3, Cystatin C, NGAL and β2-microglobulin differentiated CKD/ESKD patients from healthy control subjects. The gene discussed is RBP4; the disease is chronic kidney disease.